This invention relates to a data recording device and a data recording method for recording the video and audio data.
In recent years, discs for a magnetic disc device, optical disc device or the like have been rapidly improved in functions such as recording capacity and transfer speed. In particular, the improvement of the functions of hard disc devices used in many cases for recording and reproduction of the video and audio data has been remarkable.
On the other hand, the development of digital interfaces has progressed and digital VCR (hereinafter referred to as DV) apparatuses have started to be standardized with a digital interface of the IEEE1394 standard mounted thereon. In the IEEE1394 standard, the ISOCHRONOUS transfer system is stipulated which transfers the digital video and audio data in sequence. In a transfer system using the IEEE1394 interface, for example, a transfer system for the video and audio data of the DV format (hereinafter referred to as “DV data”) is stipulated with IEC61883.
During the progress of such technology and products a disc device having the IEEE1394 interface has been proposed. For example, a disc device described in the Japanese Patent Application H11(1999)-364633 is connected to a PC or a DV apparatus with the IEEE1394 interface and it is possible to record DV data which have been received via the IEEE1394 interface in a disc.
<Description of FIG. 25>
In the DV format, a format for transferring the DV data on the IEEE1394 bus is also stipulated. As shown in FIG. 25, in the case of DV data converted from an NTSC signal, one frame (hereinafter referred to as DV frame) is formed of 10 DIF sequences (12,000 bytes).
In each of the DIF sequences, data are arranged in the order of a header, a sub-code, a video auxiliary data (VAUX), audio data and video data. Each storage region is further divided into DIF blocks of 80 bytes which comprises an ID part of 3 bytes showing the contents of data and so on, and a data part of 77 bytes.
<Description of FIG. 26>
Data arrangement of each of the DIF sequences is shown in FIG. 26. Each of the DIF sequences is transmitted in a configuration where audio data of 1 DIF block and video data of 15 DIF blocks are alternately arranged following the header of 1 DIF block (H0), sub-codes of 2 DIF blocks (SC0, SC1) and video auxiliary data of 3 DIF blocks (VA0, VA1, VA2). In the case of DV data converted from a PAL signal, the data are formed of 12 DIF sequences.
Furthermore, in the Japanese Patent Application H10(1998)-229324, it is devised that the DV data of the above-described configuration is added with the dummy data, is made into blocks which agree with an integer times of the recording segments (sector: 512 bytes) of the hard disc and is recorded from the head of the sector so that the reproduction can be carried out from the disc in the frame unit.
However, in the case that the recording is carried out on the disc in the format transmitted over the IEEE1394 bus without change, the audio data are recorded by being scattered at the unit of 80 bytes. Therefore, in the case that the video data or the audio data are edited independently (video editing and audio editing), the problem arises that the reading out and writing in processes from the disc become complicated. The above-described editing is a process of replacing the video data or the audio data once recorded on the disc with another video data or another audio data and it is necessary to independently overwrite the recording regions for the video data or the audio data on the disc. The editing of the video data is generally referred to as “video insert” and the editing of the audio data is generally referred to as “post-recording” or “audio insert.”
A conventional data recording device using a disc device which records and reproduces the DV format signal is cited as an example and is described.
The conventional data recording device records the inputted DV format signal in the disc device in the order as it is. Accordingly, an audio signal is distributed and arranged in blocks of 80 bytes on the disc device.
On the other hand, the disc or the like generally carries out recording at the unit of a constant recording segment as the minimum unit. In the above-described example, the recording segment (sector) of the minimum unit is 512 bytes.
In the case that an audio signal on the disc device is only replaced with another audio signal, one or two recording sectors (512 bytes each) including that audio signal (80 bytes) is once read out in a buffer memory together with a video signal and so on included therein. The DV format signal read out into the buffer memory is separated (demultiplexed) into the video signal and the audio signal. The separated audio signal is further separated into the audio signals of respective channels. Only the audio signals on which post-recording is intended to be carried out are replaced with another audio signals. After that, the separated audio signals of respective channels including the audio signals of the replaced channel and the video signal are multiplexed so as to be converted into the DV format signal, and that DV format signal is recorded in the original one or two recording sectors.
Accordingly, though the data device is only doing the operation of recording from the user's point of view, the separation and the multiplexing of the signals are carried out in reality and the disc device carries out recording and reproduction. Furthermore, as described above, an amount of data which is far bigger than the amount of data essentially to be recorded is recorded and reproduced. Accordingly, the data processing speed of the data recording device becomes very slow and it becomes difficult to carry out the post-recording or the like of the video and audio signals with high data rates.
Here, the post-recording is, in general, a function of replacing and recording the audio signals of a particular channel during the period of time while video signals and audio signals are being normally reproduced.
Accordingly, it is desirable to shift naturally from a normal reproduction of the video signals and the audio signals to the post-recording operation.
This data recording device is connected to a DV apparatus which can accept the DV data via the IEEE1394 interface and furthermore the DV apparatus converts the received data into an NTSC signal so as to be outputted. The outputted NTSC signal is inputted into a TV set so that the video can be watched and the audio can be listened by the TV set. The scene where the post-recording is carried out is illustrated while the user is watching the screen of the TV set and listening to the audio from the TV speaker(s).
During the normal reproduction, the data recording device outputs a DV format signal which has been reproduced from the disc device into the IEEE1394 interface without change. The DV apparatus which receives this signal separates the DV format signal so as to be demultiplexed into the original video signals and the original audio signals of respective channels. The TV set displays the video signals on the display screen and outputs the audio signals through the speaker(s).
The user starts the post-recording by pressing the post-recording button. During the post-recording a new DV format signal, by which an audio signal of a certain channel is replaced, is recorded in the disc device and, at the same time, this new DV format signal is outputted. The generating method of this new DV format signal is, as mentioned above, carried out by separating the DV format signal read out from the disc device, multiplexing it and so on. In many cases some parts or all of the processing of these separation, multiplexing and so on are carried out by the software. In such cases the problem arises that the output of this new DV format signal is delayed because much time is needed for separation, multiplexing and so on.
In particular, the output delay of the first signal which is processed by separation and so on after the conditions is over where signals reproduced from the disc device are outputted without change, that is to say, the output delay of the first frame after the post-recording is started, tends to be a problem. In the case that the delay amount of the output of the first frame after the post-recording is started exceeds the tolerance, so that it cannot follow the ISOCHRONOUS transfer of the IEEE1394 interface (refers to the occurrence of the ISOCHRONOUS transfer period which cannot transfer a signal) there is a possibility that the problem occurs that the video and the audio of the TV set are momentarily interrupted at the time when the post-recording is started.
The ISOCHRONOUS transfer is for preventing the transfer delay amount of the sequential signals such as the video signals or the audio signals from exceeding the tolerance and, therefore, the delay amount of the data transfer by the ISOCHRONOUS transfer usually falls within a constant range. Accordingly, the apparatuses which have the IEEE1394 interface generally have only the buffer memories which are necessary by assuming the delay amount of the tolerance stipulated by the standard of the ISOCHRONOUS transfer. In the case that a large delay occurs which exceeds the delay amount of this tolerance at the starting time of the post-recording, there is a risk that the video and the audio of the TV set will be interrupted for a moment at the starting time of the post-recording.
At the time when post-recording is ended, the opposite phenomenon to this occurs. When the user presses the end button of post-recording, the above data recording device outputs a reproduction signal of the DV format from the disc device as it is in its original manner. However, at the ending time of the post-recording the data recording device still holds a signal (a signal just before the end of the post-recording period) which is undergoing the process, such as separation, and it is essentially, necessary to output this signal.
But the delay due to the process, such as separation, during the post-recording cannot be maintained as it is during the normal reproduction. For example, in the case that the operations of the normal reproduction, the post-recording, the normal reproduction and the post-recording are repeated many times, the delay is added every time so that there is the risk that the buffer memory sooner or later overflows. Therefore, at the time when the post-recording is ended, the delay is resolved in some cases by skipping the output of the delayed signals (signals which have not yet been outputted just before the end of the post-recording period). In this case, video skipping and audio skipping occur due to the skipped signals.
In order to solve this problem a data recording device is proposed which has the configuration wherein the video blocks and the audio blocks are generated at each frame so as to agree with the integer times of the recording segment (sector: 512 bytes) of the hard disc by blocking the video data and the audio data separately, and the video blocks and the audio blocks are recorded in the different regions on the hard disc.
According to the DV standard for the consumer use, it is possible to record plural stereo audio signals and there is a request to implement the above-described audio edit of each stereo audio signal which has once been recorded. In the case of the NTSC signal, the first stereo audio signal is stored in the former half part which is the DIF sequence 0 to 4 while the second stereo audio signal is stored in the latter half part which is the DIF sequence 5 to 9 in a general DV apparatus. In the case of the PAL signal, the first stereo audio signal (or the audio signals of the first and the second channels) is stored in the DIF sequence 0 to 5 and the second stereo audio signal (or the audio signals of the third and the fourth channels) is stored in the DIF sequence 6 to 11.
In the above-described conventional data recording device, however, the process of reading out or recording each of the stereo audio signal independently from or to the disc is difficult and, therefore, the problem occurs that the device is not appropriate for the operation of independent audio editing of each stereo audio signal because all of the audio data are blocked in the frame unit so as to agree with the integer times of the recording segment (sector: 512 bytes) of the hard disc.
On the other hand, in the case that the received digital data are recorded on the disc or the like as they are, it is difficult to replace (carry out post-recording), for example, the audio signal of the first channel alone from among the digital data with another audio signal.
Considering the above-described conventional problems, the present invention has the purpose of providing a data recording device which makes it possible to edit the video data and the audio data easily and independently from among the digital data recorded in the disc device.